The present invention relates to door locking devices of the type which include a plurality of bars projectable from all sides of the door into recesses formed in the door frame. The invention is particularly useful with respect to key-operated rim locks mountable adjacent to one side of the door, and is therefore described below in connection with that application.
An object of the present invention is to provide a novel locking device of the foregoing type having an arrangement which makes it extremely difficult, if possible at all, to open the lock by forcing one of the locking bars to its withdrawn position. Another object of the invention is to provide a locking device which enables the user to use a single key for operating both the rim lock and also the locking bars, thereby relieving the user of carrying two keys and of making two manipulations in order to lock and unlock the door.